C4.1 Confirm or exclude asthma

If airflow limitation is fully or substantially reversible, (FEV1 response to bronchodilator>400ml), the patient should be treated as for asthma (British Thoracic Society 2008a, Hunter 2002)

Some patients may have coexisting COPD and asthma (Global Initiative for Asthma 2017). Asthma usually runs a more variable course and dates back to a younger age. Atopy is more common and the smoking history is often relatively light (e.g., less than 15 pack-years). Airflow limitation in asthma is substantially, if not com­pletely, reversible, either spontaneously or in response to treatment. By contrast, COPD tends to be progressive, with a late onset of symptoms and a heavier smoking history (usually >15 pack-years) and the airflow obstruction is not completely reversible.

COPD patients with features of asthma should receive inhaled corticosteroid therapy (to treat the asthma component), as well as long-acting bronchodilators. LABA monotherapy should be avoided in patients who have a component of asthma (Global Initiative for Asthma 2017).